Project Summary/Abstract Offending behavior among adolescents presents a significant social and public health problem. Youth offenders experience high rates of mental health problems and substance use and abuse, which increase the likelihood of recidivism and place them at elevated risk for HIV. Youth who are incarcerated are more likely to have higher rates of mental health problems and to have committed crimes involving violence. Although incarceration affords a critical treatment opportunity, the availability and provision of mental health and substance abuse prevention interventions fall short of what is required to prevent future adverse outcomes. There is growing recognition that difficulties in emotional regulatory processes underlie mental health and substance use problems in this population. Power Source is a promising prevention intervention developed by providers who work with offending youth. Power Source is guided by a theoretical model that frames delinquent, offending, and substance use behaviors as the interplay among emotional regulatory processes and social cognitive and mental health functioning (van Goozen, 2007). Using multi-session group format, Power Source enhances social cognitive capacity and emotional regulatory processes through the combined use of cognitive behavioral skill building and mindfulness meditation. Importantly, Power Source has been adopted by a large number of juvenile detention facilities across the U.S., yet has not been subject to an efficacy trial. Thus, this 3.5 year proposal seeks to conduct a small-scale efficacy trial of the Power Source intervention, the aims of which are to: (1) examine the effects of the Power Source intervention with incarcerated youth on internalizing and externalizing behavior problems, recidivism, delinquent behavior, and substance use;(2) examine the efficacy of the intervention on its most proximal targets (emotional regulation strategies and social cognitive skills) and determine whether these mediate the effects of the intervention on behavioral outcomes;(3) explore moderators of the Power Source intervention's efficacy;and (4) explore the effects of the intervention on HIV-related sexual and substance use risk behaviors. To accomplish these aims, we will conduct a group randomized controlled trial with youth ages 16 to 18 incarcerated in New York City. This study has great potential to close a critical gap in the availability of mental health and substance abuse prevention services for incarcerated adolescents. It will also address the striking health care disparities experienced by racial and ethnic minorities who are greatly over-represented in the juvenile justice system. Results of this study will be disseminated widely and used to design a subsequent, larger-scale trial of the Power Source intervention. PUBLIC HEALTH RELEVANCE: Statement Youthful offending is a persistent problem in the US that threatens public safety and strains government spending due to the costs of incarceration and treatment. Mental health disorders, including substance abuse, are prevalent among youthful offenders and are strongly related to recidivism and further incarceration. Youthful offenders are also at high risk for HIV. This proposal seeks to examine the efficacy of a prevention intervention for incarcerated youth that targets emotional and behavioral problems, including delinquent behaviors, substance abuse and other high risk behaviors.